After manufacture, beverage containers are usually assembled in bundles and, as the case may be, subsequently packaged, in particular shrink-wrapped with shrinking foils dispensed from supply rolls and wrapped around the bundles in a continuous process during the conveyance of said bundles, which are then exposed to heat in order to produce a tight wrapping.
Such a device for wrapping foil around a group of objects is known from DE 296 08 343 U1. The device allows several objects to be wrapped in succession, this being realized by arranging one or more foil take-up elements one after the other on a traction means.
DE 603 10 836 T2 and DE 20 2008 007 497 U1, for instance, disclose further packaging machines for enveloping objects with foil sections.
In this known process for packaging bundles, in particular in the production of packages referred to as “shrink packs”, an exactly defined length of foil is wrapped around the bundle assembled for packaging. In this process, the wrapping direction of the foil corresponds to the moving direction of the machine. This single layer of wrapping is produced by means of a rod that circles the bundle while said bundle continues to be conveyed. In order to produce this circling movement, the rod is fastened to and guided by two parallel, synchronously moving chains. The currently known means for fastening the rods consist of a base support for the rods and a spring plate welded thereto. The sides that the rods are fastened to are differentiated on the basis of the machine's moving direction and the side from which the machine is operated. The two sides of the machine are accordingly classified as the so-called service side and the so-called operator side.
The foil wrapping rods on the service side are fastened, as a rule, by means of a base support disposed to be open in the direction of the chain axes. The foil rod is inserted into this opening and fixated or clamped over the spring plate by way of fastening. The foil wrapping rods on the operator side are fastened, as a rule, by means of a base support disposed to be open in the moving direction of the machine. The foil rod is pressed in between the spring plates by way of inserting it and thus at the same time fixated and clamped. Fastening of the wrapping rod support elements to the chain can be achieved, for instance, by fixing the support elements to the two hollow pin chains with dowel screws.
The foil wrapping rods can be constructed as follows. Thin sheets of metal are screwed onto both ends of a carbon fiber rod measuring approximately 20 mm in width and approximately 1000 mm in length. These sheets prevent the spring plate from milling into the rod and at the same time serve for monitoring the operating of the wrapping rods.
Several problems and disadvantages are associated with the current configuration and features. After a period of operation, the sheets of metal that are screwed onto the foil rod can, for instance, come loose. In addition, the spring plates are subject to gradual deformation at the wrapping rod support element. Furthermore, the rod material may erode, resulting in a loss of the fixation. Also, it is possible that the dowel screws for fastening the wrapping rod support elements to become deformed and damaged. The mentioned problems may cause disruptions to the manufacturing process or a collision with the bundles intended for packaging and, under unfavorable circumstances, damage to the machine.
Besides that, there are additionally the following economic disadvantages to be mentioned with regard to the prior art in fastening methods for the foil wrapping rods. For one, the welded construction of the rod support elements incurs relatively high costs. The hollow pin chain used here also causes more costs than a customary roller chain. In addition, the entire mounting assembly for the foil wrapping rod involves a considerable effort.